Wireless telegraphy.



PATENTED APR. 14, 1908.

MARGONI. WIRELESS TBLBGRAPHY.

APPLICATION FILED NOV. 28,-1902.

TIME.

' UNITED STATJELQEZXEENT oFFIo-EQ,

GUGLIELMO MARCONI, OF LONDON, ENGLAND, ASSIGNOR TO MARCONI WIRELESSTELE-g GRAPH COMPANY OF AMERICA, A CORPORATION OF NEW JERSEY.

- WIRELESS TELE GRAPHY.

Specification of Letters Patent.

Patented April 14, 1908.

Application filed November 28, 1902. Serial No. 132,974.

To all when: it may concern:

Be it known that I, Guounm o .\[.-\ReoNI, a sub ect of the King ofItaly, resid\ng at in Finch Lane, in the city of London, England,

electrician, haveinventcd certain new and useful Wireless lelegraphy, olwhich the following is a s 'mcilication.

This invention is based upon the discovery that a' core or rod ofmagnetic material which is not sensibl all'ected by high t'requcncyelm-trical oscillations or l'lertzian waves under ordinarycircumstances, becomes sensitive to them when placed in a varying ormoving magnetic tield.

My present theoryof the action of the apparatus hereinafter described isas follows, although I intend to claim this ap -iaratus broadly, whetherthis theory is correct or not:lt is a well known fact that after anychange has taken place in the magnetic force acting on a piece of iron,sometime elapses before the corresponding change in the magnetic stateof the iron is completed.- if the applied magnetic force beeithersubjected to a gradual increase followed by an equally gradualdiminution or caused to etl'ect a cyclic variation, the correspondinginduced magnetic variation in the iron will lag behind the changes inthe applied force, To this tendency to lag behind, lrot'. Ewing hasgiven the name magnetic hysteresis. It has been shown also by (ierosa, linzi, and others that the effect of alternating currents or highfrequency electrical oscillations acting upon ifim, is to reduceconsiderably the ell'e'c'ts of magnetic hysteresis, causing the metal torespond much-more readily to any influence which tends to alterits'magnetic condition. The ell'ect of electrical oscillations probablyis to bring about a momentary release of the molecules of iron from theconstraint (or .viscosity) in which, they are ordinarily held,

diminishing 'theirretentiveness and consequently decreasing the laginthe magnetic variation taking p ace inthe iron. I, therefore,anticipated'that the group of electric waves emitted by each spark of allertzian radiator would, i caused to act upon a piece of iron which isbeing subjected at the same time to the slowly varying magnetic force,produce sudden variation, in its magnetic hysteresis, which variationswould produce others of a sudden or jerkyinature in its magneticcondition. in other words, the

magnetization of the iron, instead of slowly Following the variations ofthe magnetic force applied, would ateach spark of the transmittersuddenly diminish its magnetic la-g caused by hysteresis. 'lhese, jerksin the magnetic condition of the iron would cause induced currents in acoil of wire of strength sul'licicnt to allow the signals transmitted tobe detected intelligibly on a telephone, or perhaps even read on agalvanolneter. Thejerks in the magnetic condition of the iron might alsobe detected by a telephone diaphragm applied directly thereto. 7 I

()n a core consisting of some magnetic material which may be iron,preferably ina subdivided state, such as line wires or needles, is woundone or several layers of insulated coper wire. Over this winding isplaced insuating material and over this a secondary winding of thincopper wire contained ina narrow bobbin. The ends of the windingnearestto the iron core are connected one to earth or to a capacity andthe other to an elevated conductor, or they may be connected to thesecondary of a suitable trans- .former or intensifying coil. The ends ofthe secondary winding are connected to the terminals of a telephone orother suitable receiving instrument. The secondary winding may, however,be omitted and the magnetic changes in the iron core detected by placingthe telephone diaphragm in innnediate proximity to the said core or byany other suitable means. At the ends of the cor. or in close proximityto it is Jilaccd a magnet which is so moved or revol ved as to cause aconstant change or successive reversals in the magnetization of the ironcore.

It is found that if the. electrical oscillations of suitable periodaresent from the transmit ting station according to the now well knownmethods, rapid changes are etl'ectod in the.

magnetization of the iron core, which changes produce induced currentson the winding, and these currents in their turn reproduce on thetelephone or receiving instrument the intelligible signals sent from thetransmitting station. Another successful method is to keep the magnetfixed and use an endless iron rope or core of thin wires revolving onpulleys through the windings (which in this case are separated from theiron by means of a thin glass tube to prevent chafing of the wires) inproximity to a magnet or magnets.

'Figures 1 and 2-are diagrammatic front and side elevations of thearrangement.

I to a ca acity Ewhich may be the earth, and.

varying magnctic field in sai the ot ierto the aerial conductor A. The

wire ofthe secondary winding 0 isabout .02

cm. in diameter and a sufi'icient number of. turns of it is used to givea resistance about equal to that ofthe telephone T to which its ends areconnected, d is a horseshoe magnet driven round by a clockwork mechanismat a spec of about one revolution per second or other suitable s eed;Figs. 3 and; show the'arrangement where a continuous band or metal ropeis used. In this case two stationary horseshoe magnets d d are usedwhich should be arranged with their like poles together. The core aisfiexible and passes around two pulleys e which areabout 10 cm. indiameter and are placed about 20 cm. apart. -/lhey are driven byclockwork at about the speed of one revolution every two seconds orother suitable speed. 9 is a glass tube on which the pri-' mary b iswound and through which the core (1 passes. The other parts are similarto those of the former arrangement. Either'iron or steel can be used forthe cores or revolvin rope, but best results have been obtained wienusing hard drawn iron wire or iron wire which has been considerablystretched and twisted beyond its limits of elasticity prior to beingemployed. 7

The telephone or receiving instrument T may be connected to the ends ofthe winding 6 nearest the iron and the other winding 0 be omitted, orthe iron core a may be placed-in closeproximity to a telephone diaphragmand the sudden changes of magnetism in the core can then be detected bysounds produced by the diaphragm. In this case also no second winding isrequired on the core. The formof apparatus, as shown in Figs. 1 and 2,comprising a fixed core and movable magnet, is not herein especiallyclaimed, but

constitutes the subject-matter of an application, Serial No. 1 141,398filed as a division of my resent a lCittlOIl.

W hat I claiiii is: V

'1. At a receiving-station in a wireless telegraph system, thecombination of a core of magnetic material, means for roducing a d core,and

means inductively affected by the core for receiving oscillations,substantially as described.

2. At a receiving-station in a wireless telegraph system, thecombination of a core of magnetic matenal,;means for producing a varyingmagnetic field, a coil surrounding the core, and means for causing thereceived oscillations to pass through the coil, substantially asdescribed.

3. Ata receiving-station in a wireless telegraph system, the combinationoi a core of magnetic material, means for producing a Varying magneticfield, a coil surrounding the core, means for causing the receivedoscillations to pass through the coil, a receiving instrument and asecondary mil likewise surroundin the'core and having its ends connectedto t 1e receiving inslrummit, substantially as described.

4.; At a receiving-station in a wireless lclcgraph system, thecombination of a core of magnetic material, means for producing 11varying magnetic field, a coil surrounding the core, anoscillation-receiving conductor connected, to one end of the coil, and acapacity 0011, su stantially as described.

5. At a receiving-station in a wireless tolegraph system, thecombination of a core of magnetic material, means for producing avarying magnetic field, a coil surrounding the core, an oscillatioryrceiying conductor connected to one end flthe coil, 1 capacityconnected to the other end of .fihe coil, 21 'recei'vinginstrume t andasecon coil like; wise surrounding he core and having its ends connectedto the receiving instrument, substantially as described.

6. At a receiving-station in a wireless telegraph system, anoscillation-receiving conductor, a coil connected to said conductor, acore surrounded bysaid coil, and means for producing a varying magneticiicld in the core, in combination. with a receivinginstrument,substantially as described. 7

. 7. At a recei\ *ing-station in a wireless telegraph. system, anoscillation-rccciving conductor, a coil connected to said conductor, acore surrounded by said coil, and a magnet,

and means for changing the relative positions of the core and the magnetfor producing a varying magnetic held in the core, in combination with areceiving-instrument, sub stantially as described. I I

8. At a receiving-station in a wireless tclcgraph system, anoscillation-recciving conductor, a coil connected to said conductor, acore surrounded by said coil, a niagimt, and means for moving the corethrough the hold of said magnet, for producing a varying magnetic fieldin the core, in combination with a receiving-instrument, substantiallyas described. I

9. At a receiving-station in a wireless telegraph system, anoscillation-receiving conductor, a coil connected to said conductor, awire passing through the coil and constituting a magnetic core, a magnetplaced near lUH said wire, and means for moving the wire through thecoil, for producing a varying magnetic field in the wire, in combinationwith a receiving-instrument, substantially as described.

10. 'At a receiving-station in a wireless telegraph system, anoscillation-receiving condoctor, a coil connected to said conductor, acore surrounded by said coil, means for producing a varying magneticfield in the core, and a recciviiig-instrument inductively affected bythe core, substantially as described. 1 1. At a receiving-st ation in awireless telegraph system, an o'scillation-receiv-ing condoctor, a coilconnected to saidconductor, a core surrounded -by said coil, means forpro ducing a varying magnetic licld in the core, and arecciving-telcphonc provided with a diaphragminductively all'ected bythe core,

' substant ially as described.

- 4112. At a receiving-station in a wireless tel egraph system,aniiscillation-receiving conductor, a magiietizable core constitutingthe armature oi a magnetic 'lield, connections wherebyoscillationsreceived by the receiving conductor affect the core, andmeans, operating independently of received oscillations, l'or varyingthe magnetic 'l'ield al'oresaid. ubstantially as described.

13. .At a 'receiving-station in a wireless'teh cgi aph systni,'anoscillation-rcceiving conductor, a magnetizable core constituting thearmature of a iii-agnet-ic iield, connections whereby oscillationsreceived by the receiving conductor affect the core, means, operatingindependently of received oscillations, for varying the magnetic. fieldaforesaid, and means, controlled'by the core, for making receivedsignals manifest, substantially as de- 40 scribed. i I

ll. At a receiving-station in awireless telegraph system, anoscillration-receiving conductor, a permanent magnet, a magnetizablecore placed'within the iield of said mag- 'llti, connections wherebyoscillations re.-

ccived by the receiving conductor affect the core, and means, operatingindependently of. received oscillations, for varying the magnetic fieldaforesaid, substantially as described. 15. At a receiving-station inegi'aph system, an oscillation-receiving conductor, a magnetizable coreconstituting the armature of a magnetic field, connections 5'5 wherebyoscillations received by the receiving conductor affect the core, and amotor and means operated thereby for causing variations oftlie'inagnetic field aforesaid, substantially as described.

egraph system, the combination of an oscillation-receiving conductor, acoil connected to said conductor, means for producing a magnetic fieldwhich includes said coil, and a a wireless tel- ]6. At areceiving-station in a wireless tel by said iield,

lation-recewing conductor, a. coil connected to said conductor, meansfor producing a magnetic held which includes said coil, and areceiving-instruinent inductively all'ected by said field, substantiallyas tl(-S(I'll)(*ll.

lb. At a receiving-station in a wireless telegraph system, thecombination ol-an oscillation-receiving conductor, a coil connected tosaid conductor, means l'or producing a varying magnetic held, and areceiving instrument ail'ected by said varying lield, substantially asdescribed.

It). At a receiving-station in a \\'ii'elcss telegraph system, anoscillation-receiving conductor, a coil connected to said conductor, amagnet l'orcreating a magnetic iield which includes the coil, and meansfor varying the magnetic 'lield, substani ially as described.

20. A receiver for electro-magiietic waves, having in combination, acore of magnetic material, means for maintaining the magnet-.

ization in the core, in a constantly varying state, meansforutilizing'currents produced by electro-magnetic waves for abru tlyaltering such magnetization, and an indicating mechanism operative bysuch abrupt'changes in magnetization, substantially asset forth.

.21. A receiver for electro-magnetic waves, having in combination, acore of magnetic material, means for maintaining the magnet ization inthe core in a constantly varying state, and an indicating mechanismoperative by abrupt changes in the amount ofthe magnetization producedby currents generated by electro-magnetic waves, tially as set forth.

22. At a receivingsstation in awireless t-ele graph system, anoscillation-receiving conductor,,a wave-responsive device electricallyconnected therewith, gized independently of the receipt of oscillations,for creating a magnetic field which includes the wave-responsive device,substantially as described.

substan and a magnet, ener-v 23. At a receiving-station in a wirelesstelegraph system, an oscillation-receiving conductor, awave-responsivedevice electrically connected therewith, gizedindependently of thereceipt ot' oscillations, for creating a varyingmagnetic field Which'includes the wave-responsive device, substantiallyas described, 24. At a receiving-station in a wireless telegraph system,doctor, a wave-responsive device electrically connected therewith, andmeans for constantly maintaining a magnetic iield which includes thewave-responsive device.

25. In a receiver for wireless telegrapliy, a magnet for creating amagnetic field, a magand a magnet, ener-' an oscillation-receivingconnet is varied.

netizable member located in said magnetic field, means for moving the'magnetizable member with relation to the magnet for producing varyingmagnetism in the said member.

26. In a receiver for wireless telegraph a magnet for creating a manetic field, 'a magnetizable member located field in proximity to thepoles of said magnet and means for rotating the magnctizable memberwith. relation to the poles of said magnet to Vary its magnetism.

27. In a receiver for wireless telegraphyga stationary magnet and amovable magnetitable member located in the field created by said magnet,whereby uponi movement o fllie same the magnetic field produced by themag- 28. In a receiver for Wireless telegraphy a magnet, a movable inagnetizable member located in themagnetic field created by the saidmagnet, and means for creating changes of magnetism in themovablemember; substantially as described.

29. l n a receiver for Wireless telegraphy, a

in said magneticmeans for creatin r seaoee stationary magnet amagnetizable member located in the field created by said magnet,alternations or reversals of magnetism in t c movable member, substantially as described.

30. At a receivin station in a wireless transmission systen'i, thecombination of means for producing varying magnetism in a magnetic bodysubjected to the action of the received oscillations, andlneans fordetect- 1 ing the change of magnetic conditions in said body caused bythe received oscillations.

31. At a receiving station in a system for signaling by electricaloscillations of high frequency. the combination of an oscill ceivingconductor, means l'or creating a magnetic field indcpendeiitlyoi thereccivml oscillations, means for varying said field by the said receivedoscillations and means responsive to the variations in said field forrcndcring received oscillations in telligiblc as signals.

GUGLIELMO MA'MUN-l. Witnesses:

Wirriun BLAYDES, ROBERT B. it ixsrono.

etion re-

